[Feature] Reactive multi-select options through closure, plus auto-validation

[GoodM4ven]

Changes:

• Added the ability to provide multiselect options as a closure [reactivity]
  • Created an evaluater for the closer to be called wherever the options are needed
  • Added a test for the feature, then tested everything
• Made the multi-select trigger upon selection (space key) [auto-validation]
  • Exposed validate method for that to happen

Concerns:

• Should there be a config check for whether to do the validation instantly? Or why doesn't validation happens upon selection by default?
• Honestly, I can't seem to understand how would I trigger the option re-evaluation without triggering validation first!

Issues:

• Need to re-evaluate the index, or else movement wouldn't be normal.
• Need to trigger show changes without triggering validation, because re-evaluation currently works only when everything is valid.

Todo:

• Docs; with a good example for reactivity!

Use-case:
https://github.com/laravel/prompts/assets/121377476/bfce061c-30e3-4456-93c5-84d1ec68e77a

Comments:
Dude! How many places should they have the project-name shown at in VSCodium?!!! lol

[github-actions]

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[driesvints]

@GoodM4ven feel free to resend this once you're ready.